NASA has decided to grab an asteroid rock rather than bag an asteroid

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Rather than try to bag an entire small asteroid with an unmanned probe and bring that back to Earth, NASA has decided to send an unmanned probe into orbit around an asteroid and use it to grab one of the asteroid’s boulders.

The $1.25 billion mission, which is planned to launch in December 2020, would send a robotic spacecraft for a rendezvous with an asteroid in 2022. After touching down on the asteroid’s surface, the spacecraft would snatch a boulder several meters across. The spacecraft would then orbit the asteroid for up to 400 days, testing out an idea for defending Earth from a catastrophic asteroid impact: using the spacecraft’s own gravitational field to subtly alter the asteroid’s orbit. Next, the spacecraft would bring the snatched rock back to Earth’s vicinity in 2025. Finally, as part of preparations for a possible mission to Mars, astronauts would visit and examine the rock for some 25 days, using the planned Orion spacecraft to make the trip.

From both a science perspective as well as a manned space perspective, the unmanned part of this plan is a very good idea. Whether it will get funded depends upon Congress, since its roots go back to President Obama’s April 2010 commitment to send astronauts to an asteroid by 2025. Such a commitment was never really realistic, so it has devolved to capturing a rock and sending astronauts to visit it, thus meeting Obama’s commitment in a Potemkin Village sort of way.

Much better to bring the rock back to Earth orbit where it can be captured and brought to ISS by any number of vehicles and studied there. Whether Congress will fund this in the manner proposed in order to help Obama meet his commitment however remains very doubtful.

Posted from Santa Barbara, California.



  • Tom Billings

    Since they will now only bring back a boulder from an asteroid, it is odd that we do not hear more mention of an easier option. There are boulder-sized asteroids that get captured temporarily by the Earth/Moon gravity well. They remain in fuzzy orbits for an average of 10 months, and are eventually ejected into solar orbit again.

    This asteroid population has been calculated to mass, in total, as much as 300 tons on average, at any one time. With celestial mechanics dropping 300 tons into this population every 10 months, we have a renewable resource in Space! Any group serious about participating in settling the Solar System should be paying attention to that resource.

  • pzatchok

    All we have to do is park a nice rocket with some sort of capture mechanism at one of the Lagrange points you mentioned and wait.

    We never have to move the rock from that point but we can use the rocket to stabilize it at that point until we can get a crew up to it.

  • PeterF

    A really big net made out of a lightweight material that can be drawn closed like a purse-string net should work very well. It wouldn’t even have to be very strong like a fish net. It would just be used as a structure to mount low thrust ion engines to robotically bring mass into geosynchronous orbit. Material that wouldn’t be useable to construct a permanent space station would still be used for radiation shielding. Water ice will be the most valuable material for a permanent station, so maybe we should be looking at comets that can be captured this way

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